1. Field of the Invention
This invention relates to the manufacture and use of zirconium diboride/copper (ZrB.sub.2 /Cu) composite electrodes. More specifically, the invention relates to a method of manufacturing ZrB.sub.2 /Cu composites which includes coating ZrB.sub.2 powder with a polymer, utilizing rapid prototyping or cold pressing to shape or process the polymer coated powder to a desired form, sintering the shaped form to vaporize the polymer and sinter the ZrB.sub.2 powder, and then infiltrating the sintered ZrB.sub.2 with copper. The manufacturing technique provides ZrB.sub.2 /Cu composite electrodes with minimum electrode wear rates to be used in electrode applications where minimum wear is advantageous, including electrical discharge machining electrodes.
2. Description of the Related Art
ZrB.sub.2 is a known intermetallic ceramic or cermet. However, due to its low thermal shock resistance and room temperature brittleness, ZrB.sub.2 is rarely used for industrial purposes.
ZrB.sub.2 /Cu composites are known but rarely, if ever, used in industry because of the difficulty involved in fabricating the composite. Generally, its use has been limited to research purposes. The ZrB.sub.2 /Cu composite was investigated for possible use as a high-strength refractory coating for space ships subject to laser bombardment as well as for protection upon re-entry into the earth's atmosphere.
The only known way to make parts out of ZrB.sub.2 /Cu, particularly of complex and varying topographies, would be to hot press a mixture of ZrB.sub.2 and Cu in a die that is the negative of the desired shape or to hot press a mixture and then machine it to the desired shape. Both of these processes involve significant shortcomings, including that they are very time and energy intensive and that the machining of a ZrB.sub.2 /Cu composite is known to be very difficult. Also, it is known that these techniques produce nonhomogeneous ZrB.sub.2 /Cu parts, leading to reduced performance of the parts.